Answer:
It would have taken 12day for 6person to build 12 computers
Step-by-step explanation:
Since
4person = 18days
1person = 4 x 18 = 72days
Therefore if two more person helped
4person + 2 person = 6person
6person = 72/6 = 12days
It would have taken 12day for 6person to build 12 computers
